A question paper has two parts, part A and part B, each containing

The question paper has two sets each containing 10 questions. So the student has to choose 8 from part A and 5 from part B.

$\Rightarrow$ choosing 8 questions from 10 of part $A$ in ${ }^{10} C_{8}$

$\Rightarrow$ choosing 5 questions from 10 of part $B$ in ${ }^{10} C_{5}$

$\Rightarrow$ by Multiplication principle, we get

$=$ total no. of ways in which he can attempt the paper is ${ }^{10} \mathrm{C}_{8} \times{ }^{10} \mathrm{C}_{5}$

Applying ${ }^{\mathrm{n}} \mathrm{C}_{r}=\frac{\mathrm{n} !}{\mathrm{r} !(\mathrm{n}-\mathrm{r}) !}$

$=11340$ ways